Physico-chemical characterization of sprayed beta-Ag2S thin films

Silver sulfide Ag2S thin films have been prepared on pyrex and on SnO2/pyre x substrates by the spray pyrolysis technique (Dlala et al., Europ. Phys. J . A 2, 13 (1998)) using silver acetate and thiourea as precursors. The depo sitions were carried out at 200 and 250 degreesC. The X-ray diffraction spe ctra show that a substrate temperature T-s= 250 degreesC with a concentrati on ratio x = [S]/[Ag] = 2 in the solution allows to obtain well crystallize d thin films with a preferential orientation along ((1) over bar 03) direct ion. Microprobe analysis as well as X-ray photoelectron spectroscopy (XPS) show that a nearly stoichiometric composition is obtained under these condi tions. Moreover, we noticed by the same technique the presence of oxygen an d carbon components particularly on the surface, due to a contamination eff ect. Indeed, it can be seen after etching that the intensity peaks decrease strongly, which indicated the weak proportion of these elements in the bul k of the films.